Methanol Injection for Sponge Iron Carburization
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Solution Overview
Problem
The traditional direct reduction process for converting iron ore to sponge iron is inefficient and requires additional steps for reforming and carburization, with liquid cooling agents being independently fed into the reactor, which complicates the process.
Innovation Solution
Heating methanol or ethanol to at least 700 °C and feeding it into the reactor as a fresh volume, where it evaporates and contributes to the reduction process, eliminating the need for external reforming and separate carburization, and allowing for efficient recirculation of residual gas volumes to maintain high temperatures for reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid methanol is fed into the cooling zone for carburization, then carburization of sponge iron is achieved, but the process complexity increases due to additional cooling and carburization steps
Solution Approach 1:
The patent combines the cooling zone and carburization zone into a single integrated zone. Liquid methanol is injected directly into the reduction zone where it simultaneously cools the iron ore carriers and provides carbon for carburization through vaporization and cracking. This eliminates the need for separate cooling and carburization zones, reducing process complexity while maintaining both functions.
Solution Approach 2:
The reduction zone is designed to perform multiple functions: reduction of iron ore, cooling of carriers, and carburization of sponge iron. By making the reduction zone universal and capable of handling all these tasks, the patent eliminates the need for additional dedicated zones for cooling and carburization, thereby simplifying the overall process.
2Ease of manufacture
If separate carburization and cooling liquid is fed into the reactor, then carburization and cooling are achieved, but the number of process steps increases
Solution Approach 1:
The patent merges the functions of separate carburization and cooling liquid feeding into a single liquid methanol injection step. The methanol serves dual purposes: as a cooling agent through evaporation and as a carbon source for carburization through thermal cracking. This single-step approach eliminates multiple process steps and improves operational efficiency.
3Use of energy by moving object
If external reforming step is performed, then hydrogen is obtained for reduction, but additional equipment and process steps are required
Solution Approach 1:
The patent extracts the reforming function from the external pre-treatment stage and relocates it directly into the reduction zone. Methanol is injected and reformed in-situ within the reduction zone, eliminating the need for external reforming equipment and process steps. The reforming occurs simultaneously with the reduction process, simplifying the overall system.
Solution Approach 2:
The patent performs preliminary vaporization and cracking of methanol directly in the reduction zone before the reduction reaction completes. This preliminary action of converting methanol to reactive carbon species and hydrogen occurs in-situ, eliminating the need for separate external reforming infrastructure while ensuring adequate hydrogen supply for the reduction process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances the direct reduction process by eliminating the need for external reforming and separate carburization, improving operational efficiency and reducing costs by using methanol or ethanol to achieve high temperatures for effective reduction and carburization within the reactor.
Implementation Method 1
Heating methanol or ethanol to a temperature of at least 700 °C and feeding it into the reactor essentially as fresh volume, where it evaporates and contributes to the reduction process
Implementation Method 2
at least a partial volume of the discharged gas volume is extracted and supplied to at least one process gas heater as fuel gas or part of a fuel gas and is combusted together with an oxygen-containing gas to form a combustion gas
Implementation Method 3
the remaining residual gas volume is circulated and returned to the reactor by heating it in the at least one process gas heater by the combustion gas to a temperature of at least 700 °C
Implementation Method 4
In the direct reduction process, a heterogeneous reaction takes place between the iron ore carriers and the reducing gas, during which oxygen is removed from the iron ore
Implementation Method 5
a heterogeneous reaction takes place between the iron ore carriers and the reducing gas
Implementation Method 6
the cooling zone is cooled by a cooling gas. The iron ore carrier then passes through the shaft furnace vertically from top to bottom... the cooling gas flows through the cooling zone in the opposite direction to the movement of the produced sponge iron
Implementation Method 7
Such shaft furnaces allow for good flow of reducing gas and optional cooling gas through the iron ore carrier due to the underlying chimney effect
Data Source
Figure 1
AI summary
The invention relates to a method for reducing iron ore carrier (io) to sponge iron (si) according to claim 1.